Originally these unusual
formations were known to occur in only six caves on the Nullarbor plain
in Western Australia. However, DB has seen one in a cave on Isla de Mona in Puerto Rico as well.

Briefly, stegamites are formed in black calcite and appear as "ridges" along a cave floor. It appears that
they are formed by water forced through cracks or joints. Some of the formations are
similar to vertical cave shields.
They differ from cave shields, however,
in that they are not made up of concentric calcite plates.